The occurrence of radiolarian faunas in the upper part of the Chotec Limestone is discussed in terms of faunal composition, systematics and geological implications. The most common entactinid species are treated systematically. The occurrence of radiolarians in large numbers in the rock succession began approximately 2 meters below the onset of the black shale sedimentation (Kacak Member). The abrupt sedimentological change, commonly viewed as an event therefore does not coincide with the faunal turnover, leading to a radiolarian dominance well before the onset of black shale deposition.
Radiolarians, Middle Devonian, upper Eifelian, Barrandian, Chotec Limestone, Kacak event